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Real world example of why Fireground simplex is needed.

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CyberGoth1440

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During the structure fire in Trussville last night @ Southern Comfort Conversions the hand-held's inside the building couldn't make it into the repeater to talk to the other companies responding to the scene. They switched to simplex Channel-2 (151.88Mhz), problem solved. Am I wrong in assuming that departments who use the 800Mhz TRS (like Birmingham) can't do this?
 

ff-medic

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During the structure fire in Trussville last night @ Southern Comfort Conversions the hand-held's inside the building couldn't make it into the repeater to talk to the other companies responding to the scene. They switched to simplex Channel-2 (151.88Mhz), problem solved. Am I wrong in assuming that departments who use the 800Mhz TRS (like Birmingham) can't do this?
800 MHZ, is notorious for not having any power, either in the radio, or the signal. 800 MHZ on a fireground anyway. If so, if firefighters were in the structure, the 800 MHZ signal had to penetrate the building structure to key up the repeater / mobile repeater.

Am I right in interpreting that they were 800 mhz, and switched to 151 Mhz? Hmmmm. The new Motorola Dual band portable I presume?

FF - Medic !!!
 
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CyberGoth1440

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Sorry I didn't make that clear. Trussville uses a conventional VHF repeater system, I was talking about a lot of the other local departments that use the Birmingham / Jefferson SmartZone system. I can see why Trussville Fire stayed VHF & are possibly going MotoTRBO VHF, the TRS just doesn't have good coverage in this area. Trussville PD is on the 800 & they are always "going digital" (the local term for unreadable traffic on this system) especially the handhelds.
 

ff-medic

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Again. The signal did not make it thorough the structure, to key up the repeater. But in any event, two radios talking to one another ; as long as they are on the same radio frequency ( imput and output radio freqs as well as PL's ) should still be able to communicate to each other without having a seperate
simplex freq.

And I belive, some months ago ; a similar situation / event and thread was on this very same site. No duplex operation on the fire gound.

The signal has to reach and be able to key up the repeater. If not, the repeater will not key up ; and retransmit the radio signal at an increased power. Simple radio comms.

I do not see where a simplex freq ( non repeater channel and freq ) would have benefited. Still , again , they should have been able to talk to each other radio to radio. If not, building structure, in some instances background noise - depending on the type of radio system , as well as severe electrial foundations ( electricity and electrical lines absorb radio signals ) could have made portable radio communcations difficult.

FF - Medic !!!
 

mdulrich

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Am I wrong in assuming that departments who use the 800Mhz TRS (like Birmingham) can't do this?
While I don't know if Birmingham has them, simplex fireground frequencies can and should be programmed into the radios for situations like this.

Mike
 
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While I don't know if Birmingham has them, simplex fireground frequencies can and should be programmed into the radios for situations like this.

Mike
Birmingham uses Motorola XTS 5000 portables for 800mhz so unless the simplex frequency was on 800mhz I don't think they can. Even if they could it seems like it would be hard to switch from the 800mhz trunked system over to the simplex freq in the field.

I can personally see where there still is a need for at least the capability of simplex operation. If repeaters get taken out by something like the April 27th tornadoes, users can just switch over to simplex. If a city like Birmingham lost a few 800mhz repeaters to a storm, I really don't see what they would do to compensate for it.

As for fireground simplex, I can see its uses. Seems like it would be much easier for command to radio to firefighters inside the structure without the use of a repeater. Since range isn't as big of an issue it seems likely that the signal would be able to penetrate the structure. From there, command could switch over to the main frequency if they needed to make contact with dispatch or incoming units and then back to simplex for fireground comms. In a city like Birmingham signal penetration might not be as big of an issue since the 800mhz coverage is greater, but in an area further out that doesn't have as much 800mhz coverage I can see where it would be a problem.

"Turkey talk", "going digital", etc. seems to be a very common problem all across the Birmingham/JeffCO TRS-has been ever since I started listening to them. I have no idea why its such a big problem but it is.
 

BoxAlarm187

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Birmingham uses Motorola XTS 5000 portables for 800mhz so unless the simplex frequency was on 800mhz I don't think they can. Even if they could it seems like it would be hard to switch from the 800mhz trunked system over to the simplex freq in the field.
It's just a matter of turning the knob. The final two channels in the fire department zone on our radios at work (Motorola digital 800MHz) are simplex.
 

W2NJS

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Fireground simplex channel...

During the structure fire in Trussville last night @ Southern Comfort Conversions the hand-held's inside the building couldn't make it into the repeater to talk to the other companies responding to the scene. They switched to simplex Channel-2 (151.88Mhz), problem solved. Am I wrong in assuming that departments who use the 800Mhz TRS (like Birmingham) can't do this?
Hold everything. Are you certain that an FD used a MURS channel (151.88) to call for help?

Also, just because a system is on 800 mHz does not mean you can't have simplex channels. Those channels can be P25 or analog as well. In my home area which has eight or ten coordinated, large P25 800 mHz systems there are quite a few 800 mHz channels used in simplex mode, and some of them are analog as well.

And channel changing or a multiband radio is absolutely no problem...if you're lucky enough to have an APX or a Liberty or an XG100 with you.
 

CyberGoth1440

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Yep, their Channel-2 is 151.8800Mhz, figured out that's why it's unlicensed. Now that I think about it I should scan the other MURS frequencies, could be using some of those as well.
 

signal500

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My local Fire Department uses a VHF repeater. Channel 1 is the repeater channel and Channel 2 is the fireground channel which just happens to be the output frequency of the repeater. So even if incident command is on Channel 1 for some reason, the chief can hear if any of the firefighters are in trouble inside of a building. The firefighters are trained to use channel 2 while on a fire scene including being inside any building. Works very well. The sheriff's department also reprogrammed their radios to do the same thing. Most all 800 MHz public safety systems have simplex channels programmed in their radios, but most commonly, the officers aren't trained properly to switch to them. It's the old adage, "keep it simple stupid". There are so many 'channels' to choose from on the radio that sometimes the officer gets confused easily, especially under stress.
 

W2NJS

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Yep, their Channel-2 is 151.8800Mhz, figured out that's why it's unlicensed. Now that I think about it I should scan the other MURS frequencies, could be using some of those as well.
And some kid or similar nudnick can legally come on the channel at any time and interfere with your emergency, life and death communications? You have to wonder if your systems administrators know that much about radio communications.
 

SCPD

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And some kid or similar nudnick can legally come on the channel at any time and interfere with your emergency, life and death communications? You have to wonder if your systems administrators know that much about radio communications.
I agree,I guess Trussville is to cheap to apply for a license and I would bet they are using more than 2 watts,I bet if anyone else dares to use MURS they will be told its a emergency channel to.Do they have any pl tone on it?
 
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krokus

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Wirelessly posted (BlackBerry8530/5.0.0.973 Profile/MIDP-2.1 Configuration/CLDC-1.1 VendorID/105)

800 MHz simplex is available, as I-Tac and 8-Tac. These are arranged for use with repeaters, but can be used in talk-around mode, which Motorola calls "Direct Mode"

Look in NIFOG for the details.
 
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I agree,I guess Trussville is to cheap to apply for a license and I would bet they are using more than 2 watts,I bet if anyone else dares to use MURS they will be told its a emergency channel to.Do they have any pl tone on it?
Trussville isn't cheap, "they" just cant learn how to spend money wisely. Yes, PLs are used on both channels.
 

MFRD8539

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Somebody hit it on an earlier post. Most of these problems are associated with agencies not wanting to spend money on a reliable system. They serve a large area but only put up a single repeater. 700/800 mhz is great for building penetration and trunked radio is very reliable and efficient. Of course it also does fail so simplex, whether 800/vhf/uhf, is essential for backup. Some counties have great systems where funds are spent collectively and the outcome is a robust system. Others are victims of politics where they want to control "their" cheap (low bid) system instead of looking for ways to expand existing systems to benefit everybody. That's when these problems occur you speak about.
 
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Seems weird to me that Trussville would be using a MURS channel for official emergency comms. I'm not sure of the legality of it, but what's to keep someone from screwing around with the freq. they use? Sure, they may be using PL tones but we all know how that goes... Seems like the potential liabilities involved would've made them overlook the cost of getting a proper freq. licensed.

I do stand corrected on the availability of 800mhz simplex, although I'm still pretty sure that the Birmingham/JeffCo system doesn't make use of any simplex channels.
 

CyberGoth1440

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I've wondered about the MURS thing too. "Channel-2" isn't the only simplex channel, they have talk-around on the Channel-1 Repeater output frequency. Oh well, got a feeling they will be on MotoTRBO soon anyway.
Whatever radio's they use, Trussville has a great bunch of guys working for em!
I have never heard much on the 800Mhz ICALL/ITAC frequencies except chit-chat & that was LE, no Fire / EMS.
 

ecps92

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Not Always - some states allow these when Interop [outside Agencies] is needed, but never for day-to-day or routine [fireground] use

Always check with your State as they plan the Mutual Aid channel usage into the SCIP's.

The NIFOG is only a guide and does not replace FCC/NTIA and/or your state guidelines.

Wirelessly posted (BlackBerry8530/5.0.0.973 Profile/MIDP-2.1 Configuration/CLDC-1.1 VendorID/105)

800 MHz simplex is available, as I-Tac and 8-Tac. These are arranged for use with repeaters, but can be used in talk-around mode, which Motorola calls "Direct Mode"

Look in NIFOG for the details.
 

ocguard

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I think alot of the benefit of a conventional repeater/simplex system is being missed here. Let's say a FD uses a conventional VHF repeater as it's fireground channel. The repeater-out is 154.415. The repeater in is 158.950. Units get to the fireground and, per SOP, are using the repeater. A crew gets inside and discovers that it can't hit the repeater anymore. That unit switches over to the talk-around version of the fireground channel (154.415 simplex) and goes right on working. Chances are, that interior unit can still HEAR the repeater, so they'll still hear everything going on. And units outside who are still on the repeater channel can HEAR them. A well-established department might even have a mobile radio in a chief's vehicle programmed in reverse (so that it receives the repeater-in frequency and transmits on the repeater-out frequency). This way, they could hear and talk to a unit on the repeater channel who cannot connect to the repeater.

Sure, there are options for simplex operations for departments using 800mhz trunked radio systems (or any band TRS) but there is no continuity like I mention above. If your radio is set to the TRS, and you go inside a building where your portable radio cannot connect to the TRS, you have NOTHING. You could switch to the simplex channel in your radio and hope that someone else is listening. But you have no way of knowing if anyone will hear you.

I strongly believe that fireground operations should utilize conventional/simplex radio systems. Dispatch-to-command is fine on a TRS, but you just can't be 100% sure about on-scene communications. Also, while 800mhz is wonderful, VHF has a strong place in the fire service. It's got the power to get things done. I'd even take UHF over 800mhz. Just my 2 cents.
 

cdknapp

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I wish the NFPA would come out with a standard mandating fire ground be conducted on simplex, analog. Not being able to hit a repeater is a big problem. So are many digital systems, such as P25. Even if you could hit a repeater, the voice quality under good conditions is poor (let alone inside a structure fire wearing an SCBA mask), and the lag times are bad. I have seen (heard) this causing officer safety problems on the police side already, just because of these 2 issues.
I wouldn't want to see this become a problem in fire, or EMS, for that matter.
 
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